CN115741764A

CN115741764A - Two finger manipulators of multipurpose self-adaptation

Info

Publication number: CN115741764A
Application number: CN202211462386.9A
Authority: CN
Inventors: 赵川; 刘梦华; 马亦凡; 沈明辉; 王运来; 谭嘉伟
Original assignee: Beijing Fanchuan Intelligent Robot Technology Co ltd
Current assignee: Beijing Fanchuan Intelligent Robot Technology Co ltd
Priority date: 2022-11-22
Filing date: 2022-11-22
Publication date: 2023-03-07

Abstract

The invention provides a multipurpose self-adaptive two-finger manipulator which comprises a boosting module, a flexible wrist joint, a parallel driving module and two self-adaptive fingers, wherein the boosting module is connected with the two self-adaptive fingers; the force increasing module and the parallel driving module are sequentially connected through a flexible wrist joint to realize the flexible freedom degree control of the two-finger manipulator; the adaptive fingers are driven by the parallel driving module to complete large-span parallel grabbing actions respectively, and the large-span parallel grabbing actions comprise holding actions, pinching actions and grabbing actions with external constraint force. The invention can provide the two-finger opening and closing size, surface adaptability and stable geometric constraint required from small-scale holding of the door handle to large-scale grabbing of the screwed valve, and improves the grabbing success rate of the mechanical arm and the execution efficiency of the mechanical arm operation.

Description

Multipurpose self-adaptive two-finger manipulator

Technical Field

The invention relates to a two-finger self-adaptive manipulator applied to unstructured environments such as valve twisting and door opening, in particular to a multipurpose two-finger manipulator with functions of force increasing, smoothness and self adaptation.

Background

In order to solve the operation tasks of screwing a valve, opening a door handle and the like in the human activity environment, the mechanical arm needs a multipurpose end tool to establish physical connection and motion control with an operated object, and further helps human to complete the complex operation task in the severe environment. To simplify the control complexity and the friendliness of hand-environment interaction, many manipulators based on adaptive mechanical design have been developed. However, these manipulators do not meet the performance requirements for special operations, such as full-coverage operation of the valve and the door handle in a large span dimension, contact surface adaptability required for valve operation, adaptive grasping with constraint interference, and the like.

The Chinese patent application with publication number CN104760051A discloses a two-finger manipulator with a pneumatic sucker and a clamping air bag, which comprises a palm plate, a steering engine, a vertical transmission helical gear, a four-bar mechanism, a left finger and a right finger. The palm plate is arranged at the front end of the steering engine, so that the hidden danger of sight shielding is avoided; the output shaft of the steering engine transmits power to left and right fingertips through vertical bevel gear transmission and a four-bar mechanism. The left finger and the right finger are separated when the steering engine rotates forwards and are closed when the steering engine rotates backwards. Four suckers are installed on the outer side of the finger, a clamping air bag is installed on the inner side of the finger, and a force sensor is installed at the tip of the finger. The two-finger manipulator is high in sensitivity and convenient to install, and the air bag is inflated after the manipulator grabs a workpiece, so that the workpiece can be clamped conveniently. The fingertip force sensor can feed the state of the manipulator back to the control system in time, so that the control system can sensitively judge the working state of the manipulator, and the real-time control performance of the translational manipulator is guaranteed. The two-finger manipulator can also absorb workpieces through the sucking discs, and the working capacity of the manipulator is improved. Although the fingers have complete operation and sensing capability and improve the grabbing capability through the pneumatic sucker and the clamping air bag, the fingers have excessive active control functions, depend on a matched pneumatic system to cause system complexity, are not beneficial to quick replacement and integration with a mechanical arm, are limited by grabbing postures and are not suitable for completing a valve screwing task with large torque.

Non-patent document 1 "Analysis and Synthesis of extracted compatible mechanics Based on Transmission Properties of Motion and Force" discloses a single-driver two-finger gripper in which each finger has two joints and which achieves enveloping and precise gripping; under-actuated hands are capable of adaptively gripping objects of different shapes and sizes, but their ability to grip accurately is limited due to the uncontrollable contact force and motion. The gripper realizes envelope grabbing by utilizing passive self-adaptation, realizes accurate grabbing by utilizing fingertip parallel motion, cannot realize small-scale holding to provide larger constraint force, has motion coupling in the grabbing process, and needs continuous coordinated motion of mechanical arms to make up action errors in the operation process.

Non-patent document 2 "Self-adaptive grapping process and equalization configuration analysis of a 3-DOF UACT dental finger" describes an adaptive grasping process and a balanced structure of a three-degree-of-freedom underactuated finger composed of a rope-truss unit, and the finger adopts tendon-pulley transmission and a parallel four-bar linkage mechanism to achieve grasping, and verifies the structure and the Self-adaptation of the grasping stage. However, the fingers can only complete self-adaptive coating, cannot realize parallel pinching to complete fine gripping, and the double fingers rely on double motors to complete coating movement, cannot provide the small-scale gripping of the door handle and the double-finger opening and closing scale required by large-scale gripping of the screwing valve, has surface adaptability and stable geometric constraint, and cannot complete clamping of the joint of the valve spoke and the wheel rim.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a multi-purpose finger manipulator with force-increasing, flexibility and self-adaptation, wherein the self-adaptation fingers not only complete the tasks of screwing the valve and holding the door handle, but also achieve the shape self-adaptation function of the object to be pinched and held and the local self-adaptation of the gripping action with external constraint force.

The technical scheme of the invention is as follows.

The invention provides a multipurpose self-adaptive two-finger manipulator, which comprises a boosting module, a flexible wrist joint, a parallel driving module and two self-adaptive fingers, wherein the boosting module is connected with the two self-adaptive fingers;

the boosting module and the parallel driving module are sequentially connected through a flexible wrist joint to realize flexible control of the two-finger manipulator;

the adaptive fingers are driven by the parallel driving module to complete large-span parallel grabbing actions respectively, and the large-span parallel grabbing actions comprise holding actions, pinching actions and grabbing actions with external constraint force.

Preferably, the boosting module is a single-stage planetary reducer and comprises a sun gear, a crossed roller bearing, a wrist base, a first gear shaft, a planet gear, a first bearing, an input frame, a second bearing, a second gear shaft, a third bearing and a first pin shaft;

the sun gear is fixedly connected to the input frame through a first gear shaft and provides a driving force input interface for a tail end joint of a mechanical arm connected with the input frame;

the number of the planet gears is three, the planet gears are fixed on the wrist base through three second gear shafts respectively, and driving antagonism is provided for rotation of the wrist base; the sun wheel is meshed with the three planet wheels respectively;

when the adaptive finger is not constrained by the environment, the power module controls the whole hand to rotate; when the joint of the adaptive finger and the wheel rim of the valve and the spoke establishes a constraint force, the tail end joint of the mechanical arm sequentially passes through the boosting module, the flexible wrist joint, the parallel driving module and the adaptive finger to integrally rotate and drive the valve to overcome the environmental constraint force so as to realize the task of screwing the valve.

Preferably, the flexible wrist joint comprises a base drag hook, a rotating frame drag hook, a cross rotating frame and a tension spring;

the two base drag hooks are respectively screwed on the wrist base;

the two rotating frame drag hooks are respectively screwed on the cross rotating frame; two tension springs are respectively arranged on two sides of the manipulator, and each side is connected with a base drag hook and a rotating frame drag hook;

the cross rotating frame is of a cross structure with a long shaft and a short shaft, the long shaft structure is used for providing a large movement stroke for the self-adaptive finger, and the short shaft structure provides a flexible movement supporting structure for the tension spring;

the torque direction provided by the tension spring is parallel to the finger grabbing direction and is vertical to the rotary motion of the force increasing module.

Preferably, the parallel driving module comprises a motor reducer, a first gear, a second gear, a fifth bearing, a first moving pair, a linear lead screw and a sixth bearing;

the motor reducer drives the parallel driving module through the transmission and the reinforcement of the first gear and the second gear;

the linear screw drives the first sliding pair of the two self-adaptive fingers through spiral motion, so that the parallel grabbing motion of the two fingers is controlled;

the fifth bearing and the sixth bearing provide stable movable connection for the linear lead screw, so that the linear lead screw is fixed at the long shaft part of the cross rotating frame, and a large-span double-finger opening and closing movement stroke is provided.

Preferably, each of the adaptive fingers comprises a valve screwing module, a finger base, an adaptive grabbing module and a variable size constraint module;

the self-adaptive finger is fixed on the first sliding pair, wherein the lengthening rod base is in threaded connection with the annular curved surface; the finger base is used for connecting the valve screwing module and the self-adaptive grabbing module.

Preferably, the valve screwing module comprises an extension rod base, an annular curved surface and a V-shaped surface; the lengthening rod base provides trafficability and operation space for the two-finger manipulator to grab deeply; the annular curved surface provides stable geometric constraint for continuous rotation of the joint of the rim and the spoke of the outward-expanding support valve; the V-shaped structural surface of the V-shaped surface provides geometric constraint for the curve surface of the rim of the valve which is used for executing parallel pinching, and the automatic centering function of grabbing is realized.

Preferably, the adaptive grabbing module comprises a second pin shaft, a first connecting rod, a second connecting rod, a first finger pad, a third connecting rod, a second finger pad, a torsion spring and a fourth connecting rod;

the first connecting rod, the second connecting rod, the third connecting rod and the fourth connecting rod are sequentially connected end to end through a second pin shaft to form a single-degree-of-freedom actuating mechanism; the second connecting rod and the third connecting rod are used for restricting the deformation range of the self-adaptive grabbing module through two limiting structures of the second connecting rod;

the first finger pad is connected with the second connecting rod, and the second finger pad is connected with the third connecting rod; elliptical holes are formed in the first finger pad and/or the second finger pad and used for providing deformation space and elasticity for the finger pads to be pressed.

Preferably, the size-variable constraint module comprises a sliding block, a limiting rod, a pressure spring and a spring base, and is used for providing a grabbing structure for parallel pinching containing fingertip constraint force; the sliding block is used for supporting and limiting the grabbing process, the limiting rod is used for limiting the moving range of the sliding block, and the spring base is used for providing a slide way for the sliding block; the pressure spring provides rigidity and variable supporting force for the sliding block, and the finger base is used for providing a screwed connection fixing position for the fourth connecting rod and providing a fixed connection position for the spring base.

Preferably, when the self-adaptive fingers perform parallel pinching, the hinged part of the first connecting rod and the second connecting rod is convex, the second connecting rod and the third connecting rod are concave, and a grabbing structure is formed by the second connecting rod and the third connecting rod of the double fingers; when the adaptive finger is restrained by the fingertip to pinch, the hinged part of the first connecting rod and the second connecting rod is concave, the second connecting rod and the third connecting rod are convex, and the third connecting rod of the double fingers and the inclined plane of the sliding block form a grabbing structure.

A second aspect of the invention provides a robot for unstructured environments, comprising one or more robot arms, characterized in that at least one of the robot arms ends is provided with a multi-purpose adaptive two-finger robot arm according to any one of the first aspect of the invention.

Through the technical scheme, the invention provides the multipurpose two-finger manipulator with the functions of force increasing, flexibility and self-adaption, which has three operation modes of pinching, holding and self-adaption holding with restraint, and can complete operation tasks of clamping a valve rim with large-scale span, clamping a joint of the valve spoke and the rim, holding the valve rim and a door handle, pinching an object and the like. The force increasing mechanism directly connected with the tail end joint of the mechanical arm can realize hand posture adjustment in a non-grabbing state, and the rotary driving force of the tail end joint of the mechanical arm is improved under operation tasks such as screwing a valve and the like. The wrist joint adopts a double-spring compliant mechanism to realize that the two-finger manipulator has the capability of swinging left and right after completely gripping an object, thereby being beneficial to simplifying the compliant control and improving the response speed in the operation process of the manipulator, and particularly, simplifying the large-amplitude plane motion modes of the manipulator such as the steering wheel rim and the like into a linear motion mode. The screw rod mechanism is driven by a single motor to drive two self-adaptive fingers to complete parallel movement and closing, so that the tasks of fine pinching and powerful holding with large-scale span are realized. The orthogonal design of the screw mechanism and the wrist joint flexible swing mechanism avoids the coupling of the rotary driving force and the swing direction of the wrist joint in the process of rotating the valve by the manipulator. The adaptive finger has the grabbing task passively adapting to the surface of the grabbed object and adapting to the environmental constraint, so that the grabbing success rate of the manipulator and the execution efficiency of the mechanical arm operation are improved. The invention can complete the grabbing tasks of different operation modes covering all grabbing scales under large span, wherein the task of screwing the valve is fused with the tail end of the mechanical arm to realize large output force and reduce the driving quantity, the two action modes of screwing the valve and holding the doorknob are unified through the fusion of the self-adaptive mechanism of the fingers and the structural design, and the grabbing action execution under the combined action of the main force and the external constraint force can be completed by utilizing the self-adaptive tail ends of the fingers.

Drawings

The present invention is described in detail below with reference to the attached drawings.

Fig. 1 is a schematic view of the overall structure of a two-finger robot according to the present invention.

Fig. 2 is a schematic side view of the overall structure of a two-finger robot according to the present invention.

Fig. 3 isbase:Sub>A cross-sectional view taken along the linebase:Sub>A-base:Sub>A in the side view of the overall structure of fig. 2.

Fig. 4 is a cross-sectional view taken along the plane B-B of the side view of the overall structure of fig. 2.

Fig. 5 is a schematic diagram of an adaptive finger structure according to the present invention.

The meanings of the respective reference numerals in the drawings are as follows.

1-force increasing module, 2-flexible wrist joint, 3-parallel driving module, 4-adaptive finger, 101-sun gear, 102-crossed roller bearing, 103-wrist base, 104-first gear shaft, 105-planet gear, 106-first bearing, 107-input frame, 108-second bearing, 109-second gear shaft, 110-third bearing, 111-first pin shaft, 201-base draw hook, 202-rotating frame draw hook, 203-crossed rotating frame, 204-tension spring, 301-motor reducer, 302-first gear, 303-second gear, 304-fifth bearing, 305-first moving pair, 306-linear screw, 307-sixth bearing, 401-elongated rod base, 402-annular curved surface, 403-finger base, 404-second pin shaft, 405-first connecting rod, 406-second connecting rod, 407-first connecting rod pad, 408-third connecting rod, 409-second finger pad, 410-torsion spring, 411-fourth connecting rod, 412-slider, 413-limiting rod, 415-V-shaped surface, and profile.

Detailed Description

The invention will be further explained in detail with reference to the following figures and examples:

as shown in figures 1-5, the invention provides a force-increasing, compliant and adaptive multipurpose two-finger manipulator, which comprises a force-increasing module 1, a compliant wrist joint 2, a parallel driving module 3 and two adaptive fingers 4.

As shown in figure 1, the force increasing module 1 and the parallel driving module 3 are sequentially connected through a flexible wrist joint 2 to realize the flexible freedom degree control of the two-finger manipulator. The two self-adaptive fingers 4 complete large-span parallel grabbing actions through the driving of the parallel driving module 3, wherein the self-adaptive fingers 4 not only complete tasks such as valve screwing, door handle holding and the like, but also can realize the self-adaptive function of the shape of an object to be pinched and held and the local self-adaptability of the grabbing actions containing external constraint force.

In a preferred embodiment, the boosting module 1 is a single-stage planetary reducer, and includes a sun gear 101, a fork roller bearing 102, a wrist base 103, a first gear shaft 104, a planet gear 105, a first bearing 106, an input carrier 107, a second bearing 108, a second gear shaft 109, a third bearing 110, and a first pin 111, as shown in fig. 1 and 4. The sun gear 101 is fixedly connected to the input frame 107 through a first gear shaft 104, and provides a driving force input interface for a mechanical arm end joint connected with the input frame 107. The three planet gears 105 are respectively fixed on the wrist base 103 through three second gear shafts 109, and drive antagonism is provided for rotation of the wrist base 103. The sun wheel 101 is meshed with three planet wheels 105 respectively to realize transmission and reinforcement. Wherein the power module 1 controls the entire hand rotation when the adaptive finger 4 is not constrained by the environment. When the self-adaptive finger 4 and the joint of the valve rim and the spoke establish constraint force, the tail end joint of the mechanical arm sequentially passes through the boosting module 1, the flexible wrist joint 2, the parallel driving module 3 and the self-adaptive finger 4 to integrally rotate and drive the valve to overcome the environmental constraint force so as to realize the task of screwing the valve.

As shown in FIG. 2, the compliant wrist joint 2 includes a base hook 201, a rotating frame hook 202, a cross rotating frame 203 and a tension spring 204. The two base drag hooks 201 are respectively screwed on the wrist base 103, and the two rotating frame drag hooks 202 are screwed on the cross rotating frame 203. Two tension springs 204 are respectively arranged at two sides of the manipulator, and each side is connected with the base drag hook 201 and the rotating frame drag hook 202. The cross-shaped rotating frame 203 is a cross-shaped structure having a long axis and a short axis, wherein the long axis structure is used for providing a large movement stroke for the adaptive finger 4, and the short axis structure provides a compliant movement support structure for the tension spring 204. The torque direction provided by the tension spring 204 is parallel to the finger grabbing direction and is vertical to the rotation motion of the boosting module 1. Thus, the tension spring 204, while providing local compliance to the robot wrist, may also avoid weakening the stiffness of the rotational movement when screwing the valve. Meanwhile, when the mechanical arm connected with the input frame 107 executes a door opening task, the compliance characteristic provided by the tension spring 204 ensures the stability of the self-adaptive finger 4 holding the door handle and simplifies the large swing amplitude required by the mechanical arm and the complex motion planning of multi-joint cooperation.

In a preferred embodiment, the parallel drive module 3 includes a motor reducer 301, a first gear 302, a second gear 303, a fifth bearing 304, a first moving pair 305, a linear screw 306 and a sixth bearing 307, as shown in fig. 4. The motor reducer 301 drives the parallel drive module 3 by the transmission and multiplication of the first gear 302 and the second gear 303. The linear screw 306 drives the first sliding pair 305 of the two adaptive fingers 4 through a screw motion, so as to control the parallel grabbing motion of the two fingers. The fifth bearing 304 and the sixth bearing 307 provide stable dynamic connection for the linear lead screw 306, so that the linear lead screw 306 is fixed at the long axis part of the cross rotating frame 203 and is used for providing a large-span double-finger opening and closing movement stroke.

As shown in fig. 5, the adaptive finger 4 includes an extension bar base 401, a ring-shaped curved surface 402, a finger base 403, a second pin 404, a first connecting rod 405, a second connecting rod 406, a first finger pad 407, a third connecting rod 408, a second finger pad 409, a torsion spring 410, a fourth connecting rod 411, a sliding block 412, a limiting rod 413, a compression spring 414, a spring base 415, and a V-shaped surface 416. The adaptive finger 4 is fixed on the first sliding pair 305 by screwing, wherein the extension bar base 401 is screwed with the annular curved surface 402. The extension bar base 401, the annular curved surface 402 and the V-shaped surface 416 jointly form a valve screwing module, wherein the extension bar base 401 provides a passing and operating space for deep grabbing of a two-finger manipulator, the annular curved surface 402 provides stable geometric constraint for continuous rotation of the joint of an outward-expanding support valve rim and a spoke, and the V-shaped structural surface of the V-shaped surface 416 provides geometric constraint for executing parallel pinching of a curve surface of the valve rim and realizes an automatic centering function of grabbing.

The second pin 404, the first connecting rod 405, the second connecting rod 406, the first finger pad 407, the third connecting rod 408, the second finger pad 409, the torsion spring 410 and the fourth connecting rod 411 together form a self-adaptive grabbing module. The first connecting rod 405, the second connecting rod 406, the third connecting rod 408 and the fourth connecting rod 411 are sequentially connected end to end through the second pin shaft 404, and a single-degree-of-freedom actuator is formed. The second connecting rod 406 and the third connecting rod 408 constrain the deformation range of the adaptive grabbing module through two limiting structures of the second connecting rod 406. The first finger pad 407 and the second finger pad 409 provide a larger friction coefficient and a larger contact area for finger grabbing, wherein the elliptical holes provide a deformation space and elasticity for finger pad compression. The sliding block 412, the limiting rod 413, the pressure spring 414 and the spring base 415 form size-variable constraint, and a grabbing structure is provided for parallel pinching with fingertip constraint force. Wherein the sliding block 412 provides support and limit for the grabbing process. Wherein, the limiting rod 413 limits the moving range of the sliding block 412. Wherein the spring base 415 provides a slide for the slider 412. Wherein, still set up the support slide for gag lever post 413 to and set up spacing base for pressure spring 414. Wherein, the compression spring 414 provides rigidity and variable supporting force for the sliding block 412. The finger base 403 is used for connecting the valve screwing module and the adaptive grabbing module, wherein the finger base 403 provides a screwing fixing position for the fourth connecting rod 411 and provides a fixing position for the spring base 415.

When the adaptive finger 4 performs parallel pinching, the hinged part of the first connecting rod 405 and the second connecting rod 406 is protruded, the second connecting rod 406 and the third connecting rod 408 are recessed, and the second connecting rod 406 and the third connecting rod 408 of the double fingers form a grabbing structure.

When the adaptive finger 4 is constrained by the finger tip to perform pinching, the hinged part of the first connecting rod 405 and the second connecting rod 406 is concave, the second connecting rod 406 and the third connecting rod 408 are convex, and the third connecting rod 408 of the two fingers and the inclined plane of the sliding block 412 form a grabbing structure.

The adaptive finger 4 has the following three modes of operation.

(1) Kneading operation: the two-finger manipulator is adjusted to a fingertip pinching position, and the parallel clamping mechanism of the clamping jaw is directly driven.

(2) Holding operation: the wrapping and the restraint of the door handle are realized by movably controlling the holding position of the two-finger manipulator through the mechanical arm.

(3) Grip with external restraint: when the grabbing positions of the two fingers move excessively, self-adaptive grabbing caused by position control errors is achieved through mechanical arm position control and current loop control in the closing process of the two self-adaptive fingers 4, and therefore grabbing efficiency is improved.

The adaptive finger 4 can autonomously change the grabbing mode according to the environmental constraint characteristics, which improves the intelligence of the finger grabbing process. Meanwhile, by using the operation mode (3), the control precision requirement of the mechanical arm can be reduced. For example: the independent holding of the door handle is directly completed by adjusting the distance of the finger tips contacting the door panel.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement or the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A multipurpose self-adaptive two-finger manipulator comprises a force increasing module, a flexible wrist joint, a parallel driving module and two self-adaptive fingers;

the adaptive fingers finish large-span parallel grabbing actions respectively through the driving of the parallel driving module, and the large-span parallel grabbing actions comprise holding actions, pinching actions and grabbing actions containing external constraint force.

2. The multipurpose self-adaptive two-finger manipulator according to claim 1, wherein the force boosting module is a single-stage planetary reducer and comprises a sun gear, a crossed roller bearing, a wrist base, a first gear shaft, a planet gear, a first bearing, an input frame, a second bearing, a second gear shaft, a third bearing and a first pin shaft;

3. The multipurpose self-adaptive two-finger manipulator according to claim 1, wherein the flexible wrist joint comprises a base drag hook, a rotating frame drag hook, a cross rotating frame and a tension spring;

the two base drag hooks are respectively screwed on the wrist base;

the cross rotating frame is of a cross structure with a long shaft and a short shaft, the long shaft structure is used for providing a large movement stroke for the self-adaptive finger, and the short shaft structure is used for providing a flexible movement supporting structure for the tension spring;

4. The multipurpose adaptive two-finger manipulator according to claim 1, wherein the parallel driving module comprises a motor reducer, a first gear, a second gear, a fifth bearing, a first sliding pair, a linear lead screw and a sixth bearing;

5. The multipurpose adaptive two-finger robot according to claim 4, wherein each of the adaptive fingers comprises a valve screwing module, a finger base, an adaptive grabbing module, and a variable size constraint module;

6. The multipurpose adaptive two-finger robot according to claim 5, wherein the valve screwing module comprises an extension bar base, a ring-shaped curved surface and a V-shaped surface; the lengthening rod base provides trafficability and operation space for the two-finger manipulator to grab deeply; the annular curved surface provides stable geometric constraint for continuous rotation of the joint of the rim and the spoke of the outward-expanding support valve; the V-shaped structural surface of the V-shaped surface provides geometric constraint for the curve surface of the valve rim which is used for executing parallel pinching, and realizes the automatic centering function of grabbing.

7. The multipurpose self-adaptive two-finger manipulator according to claim 5, wherein the self-adaptive grabbing module comprises a second pin shaft, a first connecting rod, a second connecting rod, a first finger pad, a third connecting rod, a second finger pad, a torsion spring and a fourth connecting rod;

the first connecting rod, the second connecting rod, the third connecting rod and the fourth connecting rod are connected end to end sequentially through a second pin shaft to form a single-degree-of-freedom executing mechanism; the second connecting rod and the third connecting rod are used for restricting the deformation range of the self-adaptive grabbing module through two limiting structures of the second connecting rod;

the first finger pad is connected with the second connecting rod, and the second finger pad is connected with the third connecting rod; elliptical holes are formed in the first finger pad and/or the second finger pad and used for providing deformation space and elasticity for the first finger pad and/or the second finger pad when the first finger pad and/or the second finger pad are pressed.

8. The multipurpose self-adaptive two-finger manipulator according to claim 7, wherein the size-variable constraint module comprises a slide block, a limiting rod, a pressure spring and a spring base, and is used for providing a grabbing structure for parallel pinching containing fingertip constraint force; the sliding block is used for supporting and limiting the grabbing process, the limiting rod is used for limiting the moving range of the sliding block, and the spring base is used for providing a slide way for the sliding block; the pressure spring provides rigidity and variable supporting force for the sliding block, and the finger base is used for providing a screwed connection fixing position for the fourth connecting rod and providing a fixed connection position for the spring base.

9. The multipurpose adaptive two-finger manipulator according to claim 7 or 8, wherein when the adaptive fingers perform parallel pinching, the hinged part of the first connecting rod and the second connecting rod is convex, the second connecting rod and the third connecting rod are concave, and a grabbing structure is formed by the second connecting rod and the third connecting rod of the two fingers; when the adaptive finger is restrained by the fingertip to pinch, the hinged part of the first connecting rod and the second connecting rod is concave, the second connecting rod and the third connecting rod are convex, and the third connecting rod of the double fingers and the inclined plane of the sliding block form a grabbing structure.

10. A robot for unstructured environments, comprising one or more robot arms, characterized in that at least one of the robot arms ends is provided with a multi-purpose adaptive two-finger robot arm according to any of claims 1-9.